FIG. 1 is a schematic diagram of a frame structure under the mode of Time Division Duplex (TDD) of Long Term Evolution (LTE) system. In such frame structure, a radio frame of 10 ms is divided into two half frames, each of which is divided into 10 time slots with respective lengths of 0.5 ms, and two adjacent time slots compose a subframe with a length of 1 ms; wherein a half frame consists of 5 subframes. In Normal Cyclic Prefix (Normal CP), a time slot consists of 7 symbols with a total length of 66.7 us; wherein the CP length of the first symbol is 5.21 us and that of the other 6 symbols are respectively 4.69 us. In Extended Cyclic Prefix (Extended CP), a time slot consists of 6 symbols, and the CP length of each of the symbols is 16.67 us.
In the frame structure of Extended Cyclic Prefix, the configuration of the subframe has the following features:
I. In order to reduce configuration number of uplink/downlink subframes, LTE TDD defines 7 configuration of uplink/downlink (UL/DL) subframe number in a radio frame as shown in table 1. All subframes are classified into 3 types, i.e., uplink subframe, downlink subframe and special subframe. As shown in table 1, in DL/UL configuration 1, subframes with subframe number of 2, 3, 7 or 8 belong to the uplink subframes for uplink transmission, subframes with subframe number of 0, 4, 5 or 9 belong to the downlink subframes for downlink transmission, and subframes with frame number of 1 or 6 are the special subframes; wherein D represents the downlink frame, U represents the uplink frame and S represents the special frame.
II. The special subframe consists of 3 special field, named as Downlink Pilot Time Slot (DwPTS), Guard Period (GP) and Uplink Pilot Time Slot (UpPTS) respectively; wherein DwPTS is used for downlink transmission and the third symbol of it is used for transmitting Primary-Synchronization Channel (P-SCH); GP is Guard Period and no transmission on it; and UpPTS is used for uplink transmission and can transmit signals such as Random Access Channel (RACH) and sounding reference signal.
TABLE 1LTE TDD uplink/downlink configurationsDownlink-DL/ULto-Uplinkconfig-Switch-pointsubframe numberurationperiodicity01234567890 5 msDSUUUDSUUU1 5 msDSUUDDSUUD2 5 msDSUDDDSUDD310 msDSUUUDDDDD410 msDSUUDDDDDD510 msDSUDDDDDDD610 msDSUUUDSUUD
III. The previous subframe of the special subframe is fixed to be used for downlink transmission, while the following subframe of the special subframe is fixed to be used for uplink transmission.
In LTE TDD, UE shall transmit the Acknowledgement/Negative Acknowledgement (ACK/NACK) response of the Physical Downlink Shared Channel (PDSCH) data in downlink subframe n on Physical Uplink Control Channel (PUCCH) in uplink subframe (n+k) (k>3) or transmit the ACK/NACK on Physical Uplink Shared Channel (PUSCH) for uplink data transmission in this uplink subframe; wherein the channel index of PUCCH is determined by the number of the lowest Control Channel Element (CCE) used for transmission of the corresponding Physical Downlink Control Channel (PDCCH).
FIG. 2 is a schematic diagram showing the multiplexing of uplink data and uplink control information. The uplink data and uplink control information may be carried in PUSCH; wherein, the uplink control information comprises Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI), Rank Indication (RI) and ACK/NACK.
In LTE TDD system, for some uplink/downlink subframe configurations, the number of downlink subframe is larger than the uplink subframe, i.e. ACK/NACKs of plural PDSCH subframes need to be feedbacked in one uplink subframe. Table 2 shows a configuration different from that in table 1, wherein, indicating the number of downlink subframes which ACK/NACK response shall be provided corresponding to the uplink subframe. If there are two transport blocks (TB) in the corresponding downlink subframes, the number shown in table 2 should be doubled
TABLE 2the number of downlink subframes which ACK/NACK responseshall be provided corresponding to the uplink subframeDownlink-DL/ULto-Uplinkconfig-Switch-pointsubframe numberurationperiodicity01234567890 5 ms——1—1——1—11——21———21—2——4————4——310 ms——322—————4——44——————5——9———————6——111——11—
At present, in the existing technologies there are only provided methods for transmitting a single ACK/NACK information and two ACK/NACK information in Physical Uplink Shared Channel (PUSCH), however for methods of transmitting more than two ACK/NACK information, no solutions have been given in the existing technologies.